In many railway car applications, it is necessary to provide some degrees of movement between the main car body and the truck supporting the body. For example, secondary suspension systems are employed to permit limited degrees of longitudinal, lateral and vertical relative movements between the car body and truck during operation. Such suspension systems often include, among other things, elastomeric members which provide restraints for stability while still permitting small movements between the bodies and absorbing some of the acceleration forces which tend to be transmitted from the truck to the car body.
In order to permit relative movements between the car body and truck, low friction slide members have been employed between the truck and car body to facilitate the movement when turns are being made by the car.
The coupling assembly of the subject invention was illustrated in a copending application entitled "An Articulated Truck Assembly", Ser. No. 306,156, filed Sept. 28, 1981, now U.S. Pat. No. 4,434,719 issued Mar. 6, 1984, and assigned to the same assignee as the present invention.
The invention in the copending application was illustrated as an element useful in a steerable truck. However, the coupling assembly per se has applications in other cases where two structural bodies are to be coupled to each other and adapted to be moved at different rates for different levels of applied differential forces. For example, the coupling assembly could replace the lateral bumper stop members found in most conventional railway cars wherein limited lateral movement between the car body and truck is permitted before the stop members prevent further relative movement therebetween.